Silver Reflector with Diffusion Barrier for Semiconductor RTP
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Solution Overview
Problem
Existing semiconductor processing chambers face inefficiencies due to the use of gold reflective materials, which are costly and have suboptimal reflective properties compared to silver, while silver tarnishes easily, rendering it ineffective for RTP applications.
Innovation Solution
A reflector with a silver reflective layer, an adhesion layer, and a diffusion barrier (such as nickel or nickel-chromium alloys) is used, along with a transparent protective layer to prevent tarnishing and enhance adhesion, allowing for improved radiation reflection and reduced heat loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold is used as the reflective coating material, then the reflector has good stability and resistance to tarnishing, but the reflective properties are suboptimal and the cost is high
Solution Approach 1:
The patent applies a multi-layer composite structure consisting of a silver reflective layer, an adhesion layer (such as chromium or nickel), and a protective overcoat layer. This composite structure combines the high reflectivity of silver with the tarnish resistance of the protective layers, achieving both optimal reflective properties and stability.
Solution Approach 2:
The patent introduces intermediate layers between the silver reflective layer and the environment. The adhesion layer (chromium or nickel) serves as a mediator to prevent direct contact between silver and corrosive environments, while the protective overcoat provides an additional barrier, thereby preventing tarnishing without compromising reflectivity.
2Loss of energy
If silver is used as the reflective coating material, then the reflective properties are optimal and the cost is reduced, but the silver tarnishes easily rendering it useless
Solution Approach 1:
The patent uses a composite multi-layer structure where silver provides optimal reflectivity while protective layers (adhesion layer and overcoat) provide tarnish resistance. This allows silver to function at its full reflective potential without direct exposure to corrosive environments.
Solution Approach 2:
The adhesion layer and protective overcoat act as intermediaries that shield the silver from environmental contaminants. These layers prevent direct interaction between silver and sulfur-containing compounds or moisture that would cause tarnishing, while allowing the silver to maintain its reflective function.
3Ease of manufacture
If a simple silver coating is applied without protective layers, then the manufacturing process is simple, but the silver tarnishes and loses reflectivity
Solution Approach 1:
The patent employs a multi-layer composite coating structure that can be applied using standard vacuum deposition techniques. While the structure is multi-layered, each layer can be deposited using conventional processes, maintaining ease of manufacture while significantly improving long-term reliability and reflectivity maintenance.
Solution Approach 2:
The adhesion layer is applied preliminary to the silver layer to prepare the substrate surface, ensuring proper adhesion and preventing direct contact between silver and the substrate. The protective overcoat is applied as a preliminary protective measure before the reflector is exposed to the processing environment, preventing tarnishing from the outset.
4Reliability
If gold coating is used instead of silver, then tarnishing is prevented, but the cost increases substantially and reflective properties are reduced
Solution Approach 1:
The patent uses thin layers of inexpensive materials (adhesion layer and protective overcoat) to protect the silver reflective layer. These protective layers are much cheaper than gold and can be applied as thin films, providing effective tarnish protection at a fraction of the cost of gold coating while maintaining superior reflective properties.
Solution Approach 2:
The composite structure replaces expensive gold with a combination of inexpensive adhesion materials (chromium, nickel) and protective coatings. This composite approach achieves the same protective function as gold at much lower material cost while providing superior reflectivity compared to gold.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of silver as a reflective material increases energy delivery efficiency to the substrate, reduces costs, and maintains reflectivity by preventing tarnishing, resulting in higher performance and lower material costs for RTP and epitaxial processing chambers.
Implementation Method 1
a reflective layer disposed on the reflector substrate and comprising silver
Implementation Method 2
an adhesion layer for adhering the reflective layer, to the reflector substrate
Implementation Method 3
a diffusion barrier between the reflective layer and the reflector substrate
Data Source
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AI summary
A silver reflector for reflecting radiation from a lamp in a semiconductor processing chamber is disclosed. The reflector may be a sleeve to be disposed in a lightpipe or part of a lamphead. The silver may be in the form of a coating on the sleeve or the lamphead.